Device for measuring a steering angle and for transferring signals between a steering column and a steering rod of a motor vehicle

Abstract

The invention concerns an arrangement for carrying out steering angle or steering wheel angle measurements (α) in motor vehicles. The arrangement uses a resolver for transmission purposes. Advantageous developments concern the use of the resolver for the additional transmission of switching information in both directions and for transmission of energy using frequency-separated or time-multiplexed transmission channels.

What is claimed is:  
     
       1. A device for measuring a steering angle and for transmitting signals between a steering rod and a steering column of a motor vehicle, the device comprising: 
       a primary winding mounted to a stationary member of the steering column;  
       a secondary winding mounted for secure rotation along with the steering rod and a steering wheel of the vehicle, said secondary winding disposed for inductive coupling to said primary winding;  
       a resolver rotor winding mounted for secure rotation along with the steering rod and the steering wheel of the vehicle, said rotor winding communicating with said secondary winding;  
       at least two mutually angled resolver stator windings inductively coupled to said rotor winding, said stator windings mounted to said stationary member of said steering column;  
       resolver electronics electrically connected to said stator windings and to said primary winding for passing resolver excitation signals to said primary winding, and for evaluating the steering angle based on said excitation signals following inductive passage thereof into said stator windings via said rotor winding;  
       a first electronic device mounted to said stationary member of the steering column and communicating with said primary winding for transmitting and receiving control signals to and from said steering wheel via said primary winding and said secondary winding;  
       a second electronic device mounted on said steering wheel and communicating with said secondary winding for transmitting and receiving said control signals to and from said first electronic device via said primary windind and said secondary winding; and  
       a first frequency filter connected between said resolver electronics and said stator windings to pass said excitation signals from said stator windings to said resolver electronics and to block passage of said control signals from said stator windings to said resolver electronics.  
     
     
       2. The device of  claim 1 , wherein said first filter is a first low pass filter. 
     
     
       3. The device of  claim 2 , further comprising a first high pass filter connected between said secondary winding and said second electronic device to pass said control signals and to block said excitation signals. 
     
     
       4. The device of  claim 3 , further comprising a second low pass filter disposed between said resolver electronics and said primary winding to pass said excitation signals and to block said control signals. 
     
     
       5. The device of  claim 3 , further comprising a second high pass filter disposed between said first electronic device and said primary winding to pass said control signals and to block said excitation signals. 
     
     
       6. The device of  claim 1 , wherein operating signals for realizing a supply of power and activation signals are supplied to said primary winding in a frequency-selected fashion. 
     
     
       7. The device of  claim 1 , wherein said second electronic device comprises at least one of a trigger circuit for an air bag and a control circuit for connection of further electrical devices mounted on said steering wheel. 
     
     
       8. A device for measuring a steering angle and for transmitting signals between a steering rod and a steering column of a motor vehicle, the device comprising: 
       a primary winding mounted to a stationary member of the steering column;  
       a secondary winding mounted for secure rotation along with the steering rod and a steering wheel of the vehicle, said secondary winding disposed for inductive coupling to said primary winding;  
       a resolver rotor winding mounted for secure rotation along with the steering rod and the steering wheel of the vehicle, said rotor winding communicating with said secondary winding;  
       at least two mutually angled resolver stator windings inductively coupled to said rotor winding, said stator windings mounted to said stationary member of said steering column;  
       resolver electronics communicating with said stator windings and with said primary winding for passing resolver excitation signals to said primary winding and for evaluating the steering angle based on said excitation signals following inductive passage thereof into said stator windings via said rotor winding;  
       a first electronic device mounted to said stationary member of the steering column and communicating with said primary winding for transmitting and receiving control signals to and from said steering wheel via said primary winding and said secondary winding and for transmitting a clock signal;  
       a second electronic device mounted on said steering wheel and communicating with said secondary winding for transmitting and receiving said control signals to and from said first electronic device via said primary winding and said secondary winding and for receiving said clock signal; and  
       a gate means connected between said resolver electronics and said primary winding and between said resolver electronics and said stator windings to pass and block said excitation signals using time multiplexing, said gate means having a clock input for accepting said clock signal to control said time multiplexing.  
     
     
       9. The device of  claim 8 , wherein said gate means is connected between said first electronic device and said primary winding for passing and blocking said control signals using said time multiplexing. 
     
     
       10. The device of  claim 9 , further comprising a first low pass filter disposed between said secondary winding and said second electronic device to pass said control signals and to block said clock signal. 
     
     
       11. The device of  claim 10 , further comprising a second low pass filter disposed between said gate means and said primary winding to pass said controls signals and said excitation signals and to block said clock signal.